Blackboard eraser



FIG. 1 is a perspective view;

FIG. 2 is a front elevational view;

FIG. 3 is a rear elevational view;

FIG. 4 is a left-side elevational view;

FIG. 5 is a right-side elevational view;

FIG. 6 is a plan view; and,

FIG. 7 is a bottom view. 

The ornamental design for a blackboard eraser, as shown. 